Posted
by
Soulskill
on Wednesday April 11, 2012 @09:52AM
from the and-are-awesome dept.

You recently got the chance to ask a group of MIT researchers questions about fusion power, and they've now finished writing some incredibly detailed answers. They discuss the things we've learned about fusion in the past decade, how long it's likely to take for fusion to power your home, the biggest problems fusion researchers are working to solve, and why it's important to continue funding fusion projects. They also delve into the specifics of tokamak operation, like dealing with disruption events and the limitations on reactor size, and provide some insight into fusion as a career. Hit the link below for a wealth of information about fusion.

1. What have we learned?
by jank1887

Fusion is one of those technologies that is always '50 years away,’ even 50 years ago, maybe even 50 years from now. So, looking at what's actually happened recently: What do we actually know now that we didn't know 10-15 years ago that gives support to the notion that we're making progress? Or, what are the 'big' things we know now? Similarly, what are the things we still don't know that we could reasonably expect to find answers for in the next 10-15 years?

MIT Researchers: As researchers in this field, we have heard the expression "Fusion is 50 years away and
always will be" more times than we would like to admit. The implication of this statement
is that no real progress has been made in the field, which is simply not true! We have
made a great deal of progress, even in the last 10–15 years (which have been very
lean times for funding). We’ll try to summarize some of the new findings, in no particular
order:

1) Internal Transport Barriers/Reversed Shear operation –
We have actually discovered a way to improve upon the performance that we get in H-
mode plasmas. These improvements come in the form for so called internal transport
barriers. In the past 10–15 years we have begun to understand how to modify the
current flowing in tokamak plasmas so that we create effectively what is a barrier in the
middle of the plasma. Like the edge barrier in H-mode plasmas, this barrier restricts
particles and energy from escaping the plasma and enhancing the overall performance.
2) I-mode –
In just the last 5 years, a new operational regime has been discovered on the Alcator
C-Mod tokamak at MIT. This is termed the I-mode, or “Improved L-mode” regime.
When the tokamak is operated in this manner it exhibits excellent energy confinement
properties, keeping the plasma hot. At the same time the plasma does an excellent
job of expelling impurities which dilute the fusion fuel and reduce the number of fusion
reactions which can occur. It is particularly important to us as it was first observed on
Alcator C-Mod, and is now under active development at many other tokamaks around
the world.

3) Development of Predictive Models –
Great advances have been made in the development of predictive computer models,
such as gyrokinetic and magnetohydrodynamic (MHD) formulations. Years of
experiments have revealed that plasma turbulence is often primarily responsible for
the loss of particles and energy from fusion reactors. In the past 10–15 years we have
developed advanced models which are thought to contain sufficient physics to simulate
plasma turbulence and predict the performance of future fusion devices. At this time we are in the process of validating these models, i.e. comparing them directly with
experiment to ensure they are correct, but we are approaching the ability to reliably
predict the performance of fusion plasmas without the need for a fusion reactor. This
can motivate engineering design and operational choices for future fusion devices.

4) Self-acceleration of the plasma (intrinsic rotation) –
Over the past decade, it has been discovered (on Alcator C-Mod and elsewhere) that
plasmas can spontaneously rotate, at speeds of tens of kilometers per second. (Imagine
the donut-shaped plasma spinning on its axis.) This turns out to have beneficial effects
for stabilizing turbulence at the edge, as the spinning plasma causes the turbulent
eddies to break up before they can carry hot plasma out of the core. This is an exciting
area of research that could have big implications for the performance of a tokamak
reactor.

5) Disruption mitigation –
One of the main problems with a tokamak is the ‘disruption’, when the plasma energy
is suddenly lost, stopping any fusion that is occurring and requiring a restart of the
reactor. (See the question below for a lot of detail about this!) In extreme cases, these
disruptions can cause damage to the wall of the tokamak – which would require repairs
before the machine can be restarted. Over the past decade, we have developed
techniques to mitigate these disruptions, causing the plasma to come to a rapid
shutdown that does not negatively affect the wall condition. Work is underway to scale
these techniques up to a reactor-size device (ITER).

6) ELM control/avoidance –
Another longstanding problem with tokamaks is periodic ‘bursts’ of energy from the
edge called Edge-Localized Modes (ELMs). In today’s devices, ELMs are not a
problem, but in ITER and future reactors, they could carry enough energy to damage
the wall in the divertor region (where most of the energy comes out). There has been
rapid progress lately (past 15 years) in ways to control these ELMs by making them
more rapid and smaller, such as using resonant magnetic perturbation (RMP) coils to
distort the shape of the confining magnetic field, or ‘pellet pacing’ (firing small pellets
of deuterium fuel into the machine 50–60 times per second, which triggers an ELM),
or vertical ‘kicks’ in which the control system suddenly jogs the plasma position a few
centimeters vertically, also triggering an ELM. Between these techniques and the
recently discovered I-mode (which doesn’t have ELMs), this is a problem that is well on
the way to being solved.

7) High-Z walls –
This is a particular point of pride for Alcator C-Mod. Running a tokamak with walls
made of refractory metals has many advantages because of the extreme capacity of
these materials to absorb heat loads, but there are disadvantages as well, such as
how radiative these high atomic number elements are if they get into the plasma as
impurities, or how metallic materials distort when they melt, rather than ablating like
carbon-fiber composites. Alcator C-Mod (which has a molybdenum wall) and other tokamaks have recently shown that it is possible to reliably run a tokamak with high-Z
refractory metal walls, which will almost certainly be a feature of future reactors.

2. Power Loss Scenario in Alcator C-Mod?
by eldavojohn

Not to raise any fears -- rather out of genuine curiosity -- what happens when the
magnetic fields that hold the 90,000,000 degrees Celsius plasma in place fail or loser
power on the Alcator C-Mod? I understand it's probably in prototype mode, but what
sort of safety advantages or disadvantages do Alcator C-Mod designs offer over
conventional, large-scale designs? Does the plasma come into contact with the toroidal
superconducting coil? Then what?

Geoff Olynyk answers: Actually, that’s exactly what my research is on! The event you
describe is called a "disruption." Holding a hot plasma stationary using magnetic fields
without it ever touching material surfaces is very difficult – Richard Feynman once
compared it to trying to "hold Jello with rubber bands." For any number of reasons, like
a magnetic coil losing power, the control system not being able to juggle the plasma
position quickly enough, or the plasma hitting a stability limit (pressure or density goes
too high), it’s possible for the plasma to hit the wall. The most important thing to know,
though, is that when this occurs (and it does, frequently, in today’s experiments –
although it’ll have to be a very rare occurrence in a real power reactor so it produces
uninterrupted electricity), it is no risk to the environment or to safety.

To understand what happens, you have to realize that the plasma is very, very light.
In the Alcator C-Mod tokamak, it has a mass of only about 0.001 grams – about one-
fiftieth as much as the smallest drop of water you can get from an eyedropper. (This
is with a plasma volume of about a cubic meter – a fusion plasma is actually a pretty
good vacuum!) So even though it’s very hot, it doesn’t actually have a lot of thermal
stored energy to flow into the wall if confinement is suddenly lost. There is actually more
energy stored in the current flowing in the plasma (in C-Mod, about a million amperes),
which also gets deposited on the wall. In C-Mod, thermal stored energy is about 50–
150 kJ and magnetic stored energy is almost 1000 kJ. The problem is that as we go to
larger machines (like ITER, or a reactor), the amount of stored energy in the plasma
scales like the cube of the size, and the wall area only scales like the square of the size.
So the energy deposited per square meter of wall area gets worse (larger) as we go up
in machine size.

The plasma doesn’t hit the superconducting coils - it hits (really, deposits its energy
on) the “first wall” of the chamber closest to the plasma. So, we do two things to make
sure that the walls can survive these disruption events. The first is making them out of
materials that can take a blast of heat, like tungsten, or else materials that ablate away
rather than melting, like carbon fiber composites. The second is to develop “disruption
mitigation” systems which can cause the plasma to radiate all its energy evenly over
the entire wall surface, spreading the heat out and lessening the chance of causing
localized melting. But I want to stress again - disruptions are an operational problem,
meaning they might cause a power plant to be offline for a while, but they’re not a safety problem. There is no chance of a runaway reaction or meltdown in a fusion reactor.

3. Ubiquitous Fusion Power
by monsted

When will fusion power my house (or vehicle)?

MIT Researchers: This is obviously an impossible question to answer, but we can give some thoughts
about when it might happen, and why. First, the current official plan is that ITER will
demonstrate net fusion gain (Q = 10, that is, ten times more fusion power out than
heating power put in) in about 2028 or 2029. (Construction will be done by about 2022
but there’s a six-year shakedown process of steadily increasing the power and learning
how to run the machine before the full-power fusion shots.) At that point, designs can
begin for a “DEMO”, which is the fusion community’s term for a demonstration power
plant. That would come online around 2040 (and would putt watts on the grid, although
probably at an economic loss at first), and would be followed by (profitable, economic)
commercial plants around 2050.

This seems like a long time, and it is, but it’s important to understand that this is not
the only possible path. You might say that we’re not a certain number of years away
from a working fusion power plant, but rather about $80-billion away (in worldwide
funding). We’ll get into this more in response to one of the other questions, but there are
other experiments that could be done in parallel with ITER that would certainly speed
up the goal of a demonstration power plant, if there were the money for it. Here is a
graph based on a 1976 ERDA (predecessor to today’s DOE) fusion development plan,
showing their four paths to a reactor, as well as a business-as-usual funding case that
would never lead to a reactor, and in black is the actual funding amounts. (All values are
adjusted to 2012 dollars.)

In the U.S. at least, fusion funding hasn’t been anywhere close to what would be
required for a “crash program” to get to a reactor. If it were, it would probably be
possible to have a demonstration reactor in about twenty years. (This is not actually that
long - given that it takes almost a decade to build a large fission reactor or hydroelectric
dam!)

Fusion has a reputation of “always being thirty years away” (or fifty, or twenty). We want
to address that head-on here: aside from a few over-optimistic predictions made in the
very early days of magnetic fusion research (the 1950s), this reputation is undeserved.
The reason it has taken so long to get to breakeven (ITER) is because since the end
of the 1970s, funding for fusion research has been continually slashed, up to today,
when the U.S. is proposing shuttering one of three remaining tokamak experiments,
the Alcator C-Mod device at MIT that we all work on. Despite this, progress has been
continuous. But if we had the money, we would be getting there quicker.

4. What are the economic numbers for a successful, commercial reactor?
by kestasjkI know that the economics of larger reactor = more economical are well known with
tokamaks. Does this mean you have a good idea of the minimum cost / generating
capacity of the first commercial reactors? If so, what do those numbers look like?7. Lower Limit on Tokamak Design
by gyepiAre there any good guesstimates on how small a tokamak-based fusion reactor (which
produces more energy than it consumes) can become? Theoretical limitations on the
size of the reactor would have obvious implications for pragmatic issues.

MIT Researchers:Questions 4 and 7 are similar and we answer them together here.

The current thinking is that a tokamak fusion reactor will be about 1 gigawatt electrical,
and about 2–3.5 gigawatts thermal (depending on how high-temperature the blanket
is and thus how thermally efficient it can be). This is about the size of a current fission
reactor or large coal-fired power plant.

Fusion researchers are working on smaller designs, though! At MIT, some students are
working on a concept for a 350–500 MW (thermal) class fusion reactor, which would be
cheaper to field and thus more likely to be built by private industry with limited access to
capital. This is still early work, though, and the economic analysis is not done yet.

Cost estimates for a new technology like fusion cannot be terribly reliable, but several
studies suggest that, with suitable developments in science and technology, the costs
could be competitive with other methods of electricity generation. We recommend you
read the ARIES-AT study (google it), which goes through all the factors that go into
the cost of electricity (COE) for a fusion reactor, and compares their concept to other
electricity generation options (fission, fossil fuels, etc.) A key advantage of fusion is
in what economists call "external costs." These are costs borne by society as a whole
and not by the generating industry. Environmental pollution, nuclear proliferation, and
military operations to protect oil supplies are all examples of external costs for energy.

5. What Problems are Holding Back Successful Reactions?
by Bucc5062

Can you explain to a non-scientist what the biggest stumbling blocks are for an effective
fusion reaction? Is it truly a matter of throwing money down an energy hole, or are there
verifiable, measurable benchmarks that lead us from one step to the next? I.e. we’ve
achieved X, now we need Y; when we get Y, we get Z and then achieve fusion. Is it the
technology holding us back, the politics, or the science?

MIT Researchers: We know exactly what we need to do. Not everything has a solution yet – that’s why it’s
still a research project! – but we generally know what the big challenges are to get to a
working magnetic fusion reactor. Here is a non-exhaustive list:

1 – Non-inductive current drive. We can’t rely on inductors to drive the plasma
current since they are inherently pulsed (not steady-state). We think that lower
hybrid current drive might be the solution, and are actively researching this on
Alcator C-Mod.

2 – Confining a 'burning plasma.' This is the big question that ITER will resolve
– can we really confine a plasma that is dominantly self-heated – that is, most
of its energy comes from fusion reactions rather than external heating. Will new
instabilities appear? Or can we confine the plasma as we expect we can.

3 – Confining a steady-state burning plasma while avoiding off-normal
events. We have to do both of the previous points at the same time! And we
can’t have disruptions too often or else the power plant won’t have a high enough
duty factor. The goal is to have disruptions (which require a shutdown) occur less
than once per year.

4 – Validated predictive capability for fusion-grade plasmas. We have made
great progress in this field already (see our answer to an earlier question), but
it’s not at the point yet that, say, fluid mechanics codes are, where Boeing can
design an entire plane in the computer before ever building a scale model. We
need our models of fusion plasma behavior to be accurate and reliable enough to
design first-of-a-kind machines that we are 100% sure will work the way we think
they will.

5 – Diagnosing a burning plasma. It’s really hard to tell any of the properties
of the plasma even today, when we use pure deuterium fuel (instead of ‘live’
deuterium–tritium fuel), and our plasmas are colder than they would be in a
reactor! You can’t, for example, stick a thermometer in to tell the temperature!
We have to use subtle effects like bouncing a laser beam off the electrons
and telling the temperature from the Doppler shift of the laser from the moving
electrons (a technique known as Thomson scattering). Making these diagnostics
work in the reactor environment, with higher plasma temperatures and a
ferocious flux of neutrons coming out, is a great challenge.

6 – Better understanding of plasma–wall interactions. The plasma is confined
by magnetic fields, and ideally doesn’t touch the wall at all, except in a very small
area called the divertor. This means that the material challenges in the divertor
are severe – we have to figure out a way to operate the plasma so that it’s hot
in the center, but cold near the divertor, so that it doesn’t erode the wall too fast.
This will be a limiting factor on how long you can run a fusion power plant for
before you have to shut it down in order to do maintenance. Ideally, we’d want
this to be every 2 years or so, like fission power plants today.

7 – Materials for plasma-facing components. We need to develop new
materials that can withstand the high temperatures of the wall of a fusion reactor
while resisting neutron damage and not becoming too activated by the neutrons
that will pass through them. (There is some progress on this front with ferritic
steels and silicon carbide.)

8 – Magnets that meet the plasma physics requirements and allow reactor
maintainability at reasonable costs. (Some of us are working on demountable superconducting coil concepts that may eventually be the solution to this!)

9 – Design and materials for tritium fuel cycle and power extraction. Fusion
reactors will breed their own tritium fuel from deuterium – this process has to be
experimentally tested on a large scale (which will obviously require a burning
plasma tokamak).

10 – Reliability, availability, maintainability, and inspectability (RAMI) of the
reactor designs. We have to show that our concepts for reactors really are as
good as we think they can be.

The point is that it’s not a money pit. There are unsolved challenges, but we know what
they are, and with adequate support, these challenges will be overcome. This is why
we are urging everyone to go to fusionfuture.org and write Congress asking them to
keep supporting U.S. fusion research! (It’s very easy – there’s a link at the right on the
website.)

6. NIMBY
by GeneralTurgidson

How do you explain the safety/benefits of fusion to a generation of people terrified of
nuclear anything?

MIT Researchers:This is where fusion really shines. The two big problems (at least, perceived problems)
of fission reactors are the risk of a meltdown, and what you do with the high-level
radioactive waste. Fusion has neither of these issues!

Regarding the first, the reason why a worst-case accident in a fission reactor can be
so devastating is because there is a lot of fuel in the reactor at any one time. There
are well known accidents at Chernobyl (where the reaction ‘ran away’, making more
power than the reactor was designed to handle) and Fukushima, where the fission chain
reaction was safely shut down, but the cores melted down when the tsunami knocked
out the cooling systems, due to ‘decay heat’ which is produced by the used fuel even
after shutdown.

In a fusion reactor, it’s a completely different story. There will be less than a gram of fuel
in a reactor at any one time—fresh deuterium–tritium fuel is continually added as it is
burned—and so a runaway reaction is simply not possible. Decay heat isn’t a problem
in a pure fusion system, again because there just isn’t any fuel sitting there undergoing
nuclear reactions once the reactor is shut down. In general, this is one area where it’s a
benefit that a fusion reaction is so hard to sustain! We have to try really hard to keep the
plasma hot enough to undergo fusion in the first place, so if we just turn off the heating
and fuelling systems, the fusion reaction will shut down very quickly.

As for the second benefit of fusion (waste), the reaction is completely different from that in a fission reactor. In fission, uranium (or other heavy elements like plutonium) split
into pieces, producing hundreds of different isotopes, some of which are radioactive,
with half-lives ranging from fractions of a second to millions of years. In fusion, the
reaction is simple, deuterium + tritium helium + neutron. So there is no “waste” from
the unburned fuel – any tritium that isn’t burned gets pumped out of the chamber and
recirculated back in.

This is not to say that there will be no radioactive waste from a fusion plant. The reactor
vessel itself will become activated because of the flux of neutrons passing through it,
and will have to be treated accordingly when the plant is decommissioned (after, say, a
50-year operational period). But it’s important to note that this kind of radioactive waste
is of a much lower level – it won’t have to be stored for very long before it will be “cool”
enough to simply bury in the ground safely. And there is active research going on into
new materials for fusion reactors that are more resistant to activation by neutrons, such
as ferritic steel and silicon carbide.

Finally, fusion has great advantages for nuclear non-proliferation. Creating enough
fission power plants to avoid climate change would mean that the plutonium moving
around the world would be enough to create about 100,000 nuclear weapons. For
fusion, it is much more difficult to use a reactor to make fuel for weapons. This is also
something that we think a nuclear-skeptical public will appreciate about fusion power.

All of us are strong supporters of fission power, and we agree that at times, the nuclear
power industry has not received a fair shake when compared to other sources of
energy. But we think that the advantages of fusion power speak for themselves, and
the public will be able to understand the risks and will support the construction of these
plants. Obviously, having media that are able to explain things clearly and fairly are a
necessity.

8. What do the numbers really look like?
by Erich

ITER is a hugely expensive project, and won't produce a commercially viable power
generation system. In a lot of areas where research is done on things which don't work
yet -- rockets, bridges, transmission systems, etc -- there's a general idea of how things
might be able to "scale up" to meet the goals. Is tokamak fusion really in sight of being a
commercially viable source of energy? If we need unobtanium to make a commercially
viable reactor, wouldn't it make sense to wait until the materials are viable before
making even larger tokamaks? Or is it still worth learning from these new, bigger, more
expensive reactors?

MIT Researchers: You are exactly correct in your statement; ITER is an expensive project which will not produce electricity upon completion. However, ITER’s main purpose is not to put watts
on the grid, but to demonstrate the scientific feasibility of fusion by creating a Q=10
plasma (10 times as much energy out as we put in). We do have a good idea of how to
proceed with devices following ITER, namely DEMO, a full demonstration fusion power
plant which will use the steam cycle to generate electricity from the fusion reactor. The
basic layout of a reactor can be found here: http://www.fusionfuture.org/what-is-alcator-
c-mod/c-mod-for-energy/

Although there is still plenty of research which remains, fusion is in sight of being a
commercially viable energy source. We believe that we now understand the physics
well enough to create the appropriate plasma conditions (this will be demonstrated on
ITER) and we are working on the engineering challenges that lay between us and a
commercial fusion reactor.

It is obviously impossible to predict when fusion will put power on the grid since the
estimate can change drastically based on demand and overall funding levels. You are
however, correct in noting that some of the biggest challenges involve the discovery/
development of materials which can resist the unique and harsh conditions associated
with fusion reactors, namely, high heat and neutron fluxes. Due to its importance to the
success of future devices, this is a very active and important area of research.

The international fusion community is attempting to address these issues in the
following manner: Given the scope of the ITER project and the time required to build
and test it, we are planning on constructing a materials testing facility named, IFMIF
which stands for International Fusion Materials Irradiation Facility. This facility should
be operated at the same time as ITER and will be addressing the materials issues
associated with an eventual fusion power plant while ITER is demonstrated the scientific
feasibility of a fusion reactor.

Given the time-scales for reactor construction, we think it would be unwise to wait
for this materials testing to be complete before starting new machine construction.
Addressing the remaining problems in parallel will most likely result in the quickest path
to fusion energy.

9. Careers in Fusion?
by benjfowler

As practicing researchers, can you tell us about the health of the pipeline of young
researchers coming into the field? Is there a glut of trained physicists at this stage, or
is there still a need for trained specialists to enter the field, especially with ITER and
follow-on machines coming online in the next couple of decades?

Nathan Howard answers: At this point in time fusion is actually a pretty healthy field in terms of young researchers
and with emergence of the next generation devices such as ITER, there should be an
influx of researchers stepping up to meet the need for trained specialists on these next gen devices. Currently in Europe and Asia, emphasis on fusion research is ramping up
to support the research needs. These newly trained researchers are going to be the
scientists working on ITER in 10-15 years.

Unfortunately, the US fusion program is in danger of going the opposite direction of the
Asian and European programs. The current proposals made by the US are threatening
the health of fusion in the US. The President’s 2013 budget proposal calls for drastic
cuts to the domestic fusion budget to pay for increased funding for the ITER budget.
However, if these cuts continue, there will not be a field for the young researchers to
enter and the US fusion program is in danger of dissolving before ITER comes online.

This does not mean that a need for trained specialist will not remain, it just means that
the young researchers in Europe and Asia will be filling these positions. Dr. Stewart
Prager, the head of Princeton Plasma Physics Lab said it best, “We have a clear choice
before us: The United States can either design and build fusion energy plants or we can
buy them from Asia or Europe.”

As a young researcher myself, I am particularly affected by the choices that the US is
currently making. Myself and other graduate students have been urging others who
support fusion research to contact congress and tell them to continue to fund domestic
fusion research. We put together a website, www.fusionfuture.org, which provides more
information and people the ability to quickly and easily contact their congressmen to tell
them to support research. Please support US fusion research and check out the site.

12. Patents?
by Anonymous Coward

Will patents get in the way of your research?

MIT Researchers: In general, we find that the tokamak labs of the world are extremely cooperative;
patents have never been a problem. It does seem likely that the technologies
supporting power plants will be highly patentable, but the sort of scientific knowledge
we’re accumulating at present really isn’t. At some point, we expect to move from a
collaborative to a competitive phase – but we’re not there yet.

11. What level of investment would get fusion going?
by TragekDo you think a program the size of the Apollo program could kickstart fusion to general
availability? Or would a smaller program suffice?14. What could you do with unlimited resources?
by petes_PoVGiven $1 trillion, the pick of the best brains in the world to work willingly on the project, a
large enough location away from any and all governmental regulation and every facility
you could ever need - when would fusion be commercially viable?

MIT Researchers:Questions 11 and 14 are similar and we have answered them together.

Any kind of question asking about a hypothetical massive increase in funding is tricky
to answer. We probably couldn’t even spend a trillion dollars if we wanted to – just
because it would take a long time to get enough people trained in plasma physics and
fusion energy.

We can say this: an increase in funding would allow for different paths to be tried in
parallel, like stellarators, tokamaks (ITER), spherical tokamaks, etc. Plus, we could build
a facility in the United States to study the problem of plasma–wall interactions, which
is a very important topic that has not been adequately studied up to this point (see our
answer above about what steps are needed to get to a reactor).

We think that we’re roughly $80-billion away from a reactor. At current levels of funding
(worldwide), that’s about 40 years. Even given access to huge amounts of money,
it’s unlikely that a working reactor could be built in less than a decade – there are just
too many facilities to build between current devices and a full-scale reactor in order to
ensure success. But we could certainly do it faster than 40 years!

We want to note that “crash” programs like Apollo or the Manhattan Project succeeded
because they took risks – they started work on building their systems before they
had done all the homework. That is inherently risky, but these risks are mitigated by
pursuing alternatives in parallel. Something similar could be done in fusion, given the
money.

15. Your favorite books?
by eldavojohn

I'm not a physicist (software guy), but I've taken a few physics classes. At an early age
I found a tattered copy of George Gamow's One Two Three . . . Infinity, which, although
incorrect in some parts (I guess that's why they revised it and that's why 'speculations'
was in the title), was perfectly written for my then-fifth-grade mind. It set me on a path
toward science, and a few weeks ago I saw the same 1960s Viking Press edition and
flipped through it, noticing what was slightly off and remembering it. I've since grown to
love other obvious books by authors like Hawking, Penrose, Hofstadter, etc.
So, quite simply, what are your favorite books for all minds, young and old? Also, can
you annotate which are written for the layman's entry into the given field and which are
written to encompass the field for the researcher? I find that some books start off with
the jargon so strong and the references and footnotes so thick that you start to have
to re-read every paragraph, as they're clearly condensing entire historic papers into
lengthy sentences. Any fiction books worthy of influencing your work and desires?

Ian Hutchinson: My all time favorite novel is Godric by Fredrick Buechner. It's a wonderful first-person
portrait of the prior life of a medieval hermit. My favorite physics teaching text is the Feynman Lectures on Physics, which comes
from a remarkable effort by the most widely acclaimed american physicist of the 20th
century to explain really advanced physics to undergraduates.

I really don't enjoy the genre of books that combine science popularization
with metaphysical speculation. They are of course quite popular, but most are
philosophically naive in a way that I find annoying.

Anne White: I like detective/adventure stories. I also enjoy reading plays, poetry and short stories –
some authors I read over and over are Wolfgang Borchert, Julio Cortazar, Ray Bradbury
and Samuel Beckett.

Recently, I've enjoyed reading The End of the Affair by Graham Greene, People of the
Book by Geraldine Brooks, Jane Eyre by Charlotte Bronte and Her Fearful Symmetry by
Audrey Niffenegger.

Influential books/stories that I remember reading when I was young : The Pearl (John
Steinbeck), Catch-22 (Joseph Heller), Flatland, and Ender's Game.

Dennis Whyte:

For science non-fiction books, it’s a tie: The Selfish Gene by Richard Dawkins,
and Wonderful Life by Stephen Jay Gould.

Novel (in general subject area of science): The Baroque Cycle by Neal
Stephenson

Speculative fiction: Starship Troopers by Robert Heinlein

Geoff Olynyk:The Making of the Atomic Bomb by Richard Rhodes is the best non-fiction book I’ve ever read. It’s a bit long, but is a fascinating, well-written exploration of the project to
develop the atom bomb (both in the U.S. and elsewhere).

This is not a science book, but The Rebel Sell by Joseph Heath and Andrew
Potter (sold in the United States as Nation of Rebels) changed my life. I was into
counterculture, "culture jamming," anti-advertising, that kind of stuff, and this book made
me seriously reconsider all of it. I now understand that trying to be unique is futile in
a world of seven billion, and I should just try to be a good person and do good for the
world (hence working on fusion!) Potter’s follow-up The Authenticity Hoax, explores the
search for authenticity in more detail, but it’s not nearly as good of a book as Rebel Sell.

Nathan Howard: I first became interested in physics by reading about astrophysics. I was specifically
interested in black holes and so one of the first books I read (after some of the popular
books by Hawking which are written for general audiences, e.g. A Brief History of Time)
was a book by Kip S. Thorne called Black Holes and Time Warps. I really enjoyed this
book. It did not require much technical background, just some basic mathematics, and it
gave good explanations of black holes, relativity, and gravitational waves.

16. Why is fusion more useful than exploiting thorium?
by gestalt_n_pepper

I understand that in the long term, we would want fusion. But we face increasing energy
problems over the next 50 years and severe energy problems before 2100. Wouldn't
it make sense to allocate research and development resources to something that we
know works?

MIT Researchers: First of all, fusion will be putting watts on the grid before 2100. It’s not going to be
tomorrow, but it’s not going to be a hundred years, either.

We know how to build thorium fission reactors. It's been done. They have none of the
major attractions of a fusion reactor in terms of safety, fuel resources, reduced waste,
or non-proliferation. Worldwide thorium fuel resources are about the same as those of
uranium. Thorium reactors might become part of the commercial fission reactor mix
in the future, but they don't offer transformative possibilities for nuclear power the way
fusion does.

That said, we think that the that the scale of the energy/climate problem demands that
we (meaning: government and private industry where appropriate) pursue multiple lines
of development into new energy sources. Obviously nobody wants to waste taxpayer
money, so all proposals have to be evaluated for chance of success – but today, it’s
limited by funding more than by a lack of good ideas. This shouldn’t be the case.

The key thing we want to get across is that it shouldn’t be a contest between “fund
fusion” or “fund thorium research”. Fusion is extremely important for humankind and should be funded – if thorium fission also has promise, it should be funded too.

17. How is fusion power harnessed?
by circletimessquare

The talk is always about reaching break-even with fusion. What about capturing the
power? Are we generating heat that will drive steam turbines? What schemes exist for
capture and harnessing the power generated by fusion?

MIT Researchers: In a magnetic fusion reactor, each deuterium-tritium fusion produces a 3.5 MeV (mega-
electronvolt) alpha particle (helium nucleus) which deposits its energy in the plasma
(this self-heating is how you can have an ‘ignited’ plasma which doesn’t require much
or any external heating), and a 14.1 MeV neutron, which deposits its energy in a thick
lithium blanket surrounding the toroidal reaction chamber. But in the end, all of it comes
out as heat!

For a conservative fusion reactor design, this heat would be removed by a primary
cooling loop (high-pressure steam or some sort of liquid metal) which would give the
heat to a secondary steam loop (Rankine cycle) in a heat exchanger (steam generator).
The steam would then turn a turbine, producing electricity, just like in a fission or coal
power plant.

Of course, with a thermal process like a steam cycle, one is always limited by the
Carnot efficiency, which increases as the temperature of the high-temperature reservoir
goes up. So there are also designs to use a very high-temperature (800–1000 C) gas
cooling loop and a Brayton cycle.

But the short answer is: the alpha power is captured by the plasma, and the neutron
power is captured by the blanket. It all comes out as heat, which is used to heat a
working fluid, which turns a turbine, producing electricity. This is not expected to be a
technological problem – the challenge is in getting a confined thermonuclear plasma to
produce the fusion energy in the first place!

19. Fusion Milestone Prizes?
by Baldrson

In 1992, with the assistance of fusion technologists such as Robert W. Bussard, I developed legislative language for a series of 12 milestones, each of which would be awarded a $(1992)100M prize for the achievement of objectives toward the attainment of practical fusion energy. This legislation also provided a grace period during which scientists and technologists that had been working on the US fusion program would be provided full salaries, without obligation, during which time they could seek support for their ideas to achieve these milestones. This legislation presaged a number of other prizes including the X-Prize and BAFAR / CATS prize. In 1995, Robert W. Bussard submitted this legislation to all relevant Congressional committees, copying all US plasma physics laboratories. Needless to say, the legislation wasn't passed. Do you think the time is right?

MIT Researchers: We think that the current approach, in which government-funded labs are not in direct
competition, but have to justify their funding to the agency (in our case, the DOE), is
the best option for the moment. Perhaps the X-PRIZE approach might work for the
alternative concepts? (see our answer below regarding Polywell/Dense Plasma Focus/
IEC etc.)

20. ITER
by MpVpRb

Is the ITER project good science? Or is it a politically-motivated, pork-laden
boondoggle?

MIT Researchers: ITER is absolutely good science. Governments representing over half the population
of the world are backing the project because it is the logical next step – a prototype
reactor that will produce ten times more fusion energy than heating power put in, for
a few minutes at a time. It is also pushing forward the development of fusion reactor
technology (materials, control systems, remote handling systems, etc.). The U.S.
fusion community endorsed ITER as the best option for a next-step experiment at the
Snowmass II conference in 2002 (see proceedings here).

All of that said, the cost of ITER has risen substantially from the original estimates, and
because overall magnetic fusion funding has remained nearly flat in the United States,
the U.S. contribution to ITER is threatening to swallow up the entire domestic program.
This is starting with the planned closure of Alcator C-Mod in September 2012, but
unless more money is allocated to fusion research, all three U.S. tokamak facilities are
at risk in the next few years.

Graduate students at Alcator C-Mod have put together a web page explaining the
problem: http://www.fusionfuture.org/faq/the-fusion-budget-problem/ and we urge you to
go to this website and click the link to contact your member of Congress and urge them
to fully fund a strong domestic program and the U.S. contribution to ITER!

21. NIF
by Grond

Is the NIF approach even plausibly capable of generating electricity in a useful way? Or
is it purely a research platform / smokescreen for nuclear weapons research?

MIT Researchers: The primary mission of the National Ignition Facility (NIF) is "stockpile stewardship."
That is, to ensure that U.S. nuclear weapons continue to be a credible deterrent. This
is why NIF is funded by the National Nuclear Security Agency (the agency in charge of
the nation’s nuclear stockpile), not the DOE Fusion Energy Sciences program. Thus,
the weapons research mission of NIF is not a smokescreen, but is actually the publicly
acknowledged primary objective for the facility.

Some researchers at NIF believe that their inertial fusion approach can be used for
an energy source as well. We don’t want to speculate here on the plausibility of the
LIFE (Laser Inertial Fusion Energy) concept. There is a National Academy of Science
review of the prospects of inertial fusion energy under way right now; the final report is
expected to be published before the end of this year.

18. Dense Plasma Focus
by mbradmoodyDo you see any merit in the "dense plasma focus" approach to commercial fusion power
production, specifically the work of the Lawrenceville Plasma Physics group?22. Focus Fusion / aneutronic fusion?
by mwk88Focus Fusion Society is posting research on their project to do aneutronic (e.g. Proton
Boron (pB11)) fusion. The concept sounds great, and as an engineer, I find several
parts of their design, such as direct extraction of electric power, to be elegant. Is
this credible research or pie-in-the-sky? I have not seen much mention of them in
mainstream fusion research.23. Polywell Fusion
by mknewmanWhat do you think of the efforts at EMC2 Fusion and Polywell Fusion? They seem to
be making real, measurable, and open results, but the mainstream physics community
seems to ignore this progress.24. What’s wrong with IECs / Fusor?
by claytongulickWhy aren't IEC reactors based on Farnsworth's designs taken more seriously? From
what I understand, IECs have been more effective at producing fusion, and they are
cheap to build. People even build them in the garage. From everything I've read, no one
really takes the "fusor" seriously in the fusion science realm, and it's considered a dead
line of inquiry. I've never understood why.

MIT Researchers:These four questions (18, 22–24) are answered together here.

None of us are experts on inertial electrostatic confinement, magnetized target fusion
/ dense plasma focus, or Polywells, and so we don’t want to say too much about the
specifics of those designs. We can say the following:

1. The amount of money that is being spent, especially in the United States, on fusion
is far lower than the field deserves, given its track record and potential. This sounds
self-serving, but we think it’s justifiable based on the facts. The graph we posted above
shows how the fusion budget is far lower today than it was thirty years ago, even as we
continue to make steady progress toward a reactor and the seriousness of the coupled
energy/climate problem becomes more obvious.

The alternate confinement concepts program has also seen cuts. (“Alternative” in DOE Fusion Energy Sciences parlance means, basically, anything that isn’t tokamaks,
stellarators, or laser [inertial] fusion.) The Levitated Dipole Experiment, an innovative
magnetic-confinement arrangement based on planetary magnetic fields, was cancelled
just as they were about to add significant auxiliary heating for the first time. And these
small-scale alternative confinement projects are not very expensive! Some of these
alternative concepts may very well be promising and deserve taxpayer money to be
developed.

2. But on the other hand, these groups need to show that they deserve funding. It’s not
enough to just tease these promising results and be secretive about the methods or
technologies. Public funding can only come when the details are published in the open
literature, and subjected to the scrutiny of peer review and the wider community reading
the papers. The (hot) fusion community is still living with the aftermath of the cold fusion
scandal from a quarter century ago - so it’s very important for the proponents of these
alternate concepts to push the researchers to publish their results in peer-reviewed
journals. Whatever negatives the tokamak might have, one thing you can’t say about it
is that the research has been too secretive, and this has allowed the funding agencies
to make the judgement that the tokamak is currently the most promising route to a
fusion reactor, which is why this line of research gets the most money.

Okay, I am definitely not a nuclear physicist and I did poorly in chemistry. Could I have the reader's digest form of this? I'm very curious about fusion because, on the surface, it appears to be cleaner than fission reaction. Does it still have background radiation?

Also...There was also a lot of talk about how difficult it is to stabilize the hot plasma. Apparently, they spend years studying how to reduce "disruptions" in the trapped plasma caused by changes in currents and pressures.

Emphasis on the fact the ITER should prove that we can get more energy out of the hot plasma than it takes to keep it hot. After that, it's another 20 years to build a demonstration reactor, that will generate power from steam.

Hi. This is Nathan here. I am one of the interviewees on this Q/A. I will try to briefly answer your question. Yes, there is some radiation released from nuclear fusion reactions. However, the important aspect is that the radiactive byproducts of nuclear fusion are NOT the long-lived radioactive waste that comes as the result of nuclear fission reactors. Therefore, there is no issue with waste disposal. There is only sort of low-level byproducts of nuclear fusion and it is inherently safe (there is no possibility of a meltdown like in a fission reactor). Myself and other researchers have put togehter a website written for the general public which can answer some of these questions. I encourage you to check out www.fusionfuture.org if you want some more information on nuclear fusion and on our tokamak at MIT, Alcator C-Mod. The 2013 presidential budget actually cuts our funding and we started this website to try to inform people about fusion and our machine. It has a good background section that you should check out for more answers and if you want to support fusion reserach in the US, there is a very easy way to contact your congressmen (1-2 minutes). I hope that answered your question or you can find more answers on the website, if not, ask again and I will try to provide you with more information.

However, the important aspect is that the radiactive byproducts of nuclear fusion are NOT the long-lived radioactive waste that comes as the result of nuclear fission reactors. Therefore, there is no issue with waste disposal.

The issue with nuclear waste disposal in the US isn't about whether it's high or low level. (Though many like to frame it as such.) Rather, it's about the fact that it has to be sequestered for extended periods of time, something fusion reactors have to deal with as well.

This was answered scientifically in question 6, but I'll try to give a plain-language overview.

Fusion does not generate any weird radioactive isotopes like Fission does. It -does- generate a bunch of energetic neutrons, which both transfer energy to the electricity making part of an operating plant and can interact with whatever material the thermal shell is made from, possibly producing higher isotopes of that material.

They currently estimate that, after 50 years or so, the shell would need to be replaced and would indeed be generating background radiation, but they have been researching materials for it to minimize the long-term issues.

Other than that, we're good. Remember that most of the earth's current energy actually comes from our handy neighboring fusion reactor...

Fusion does not generate any weird radioactive isotopes like Fission does.

Here is the standard/. car analogy in very non-technical terms:

Fission is like making money by running cars thru a shredder and selling the shredded bits for recycling. You have no control over the input stream and sometimes toxic paint residue shows up in the output of the shredder. Tough shite you're going to have to decontaminate it or bury it or otherwise figure out something to do with toxic paint residue. In the big picture its not a big deal, but that reside does accumulate... Seems an unavoidabl

Fusion still emits radiation (mostly neutrons). It also produces radioactive waste (mostly because of the neutrons bashing into things). But the isotopes involved are much shorter lived than the isotopes involved in fission.

It's also much safer than fission, because the reaction is not an emergent property of just bringing chunks of fuel into close proximity. If you turn off the power to a fusion reactor, it just stops. If you do that to a fission reactor, you may have a meltdown.

I think it's pretty safe to predict that if fusion-based power plants are ever built at full-scale the cost per kilowatt won't be any lower than from whatever competing technology is generating the bulk of a country's power at that time. Between the onerous regulatory requirements that will be put in place, the greed of the contractors building the plant and the shareholder demands of the utility company we'll never see truly low-cost electricity. The fossil fuel problem may be solved but your pocketbook wo

The trick here isn't to look at the next competitior, it's not like there will be a lock on fusion technology to one company; at least not all that long. It's to look at the production model. Grid Electric is a 'natural monopoly', so I believe that the best model for it is as a customer-owned cooperative business. Their goal should be the stable and reliable production of low cost electricity for it's customers/owners.

Nuclear plants became expensive because of all the fear about them delaying construction

A big part of the cost of fission plants are decommissioning cost. With coal fired and nat. gas-combustion plants, you're adding to the GG climate change effects and, while those costs are externalized, at some point we will realize they are too high for civilization as a whole. Perhaps in 10-15 years, China will finally get a reality check on their increasing energy needs, the resulting climate impact from classical energy sources and, with the ITER results in hand, will engage in a crash fusion developmen

As researchers in this field, we have heard the expression "Fusion is 50 years away and always will be" more times than we would like to admit. The implication of this statement is that no real progress has been made in the field, which is simply not true!

1) with enough time and money we will get a working fusion reactor2) and then everything will be great

I suspect #1 is largely true. However, I am largely of the opinion that #2 is absolutely *not* true.

Let's compare a fission reactor with a fusion one. To start with, the vast majority of the generation side of the system is the same - pumps cycle some sort of working fluid through the "core", cooling the core and heating the fluid. The heat in the fluid is then used

Interestingly, D production is much like Aluminum production, it primarily is electrically driven. And if you have a working fusion reactor, you conveniently have... free electricity, therefore free D.

As an ex-chemist there are neutron efficiency reasons not to do it, but from a chemical standpoint there is no reason not to use a nice boring non-reactive lithium compound. Most/.ers would probably benefit from some lithium orotate in their diet... As an example of what I'm talking about, probably two dec

None of what you say is individually wrong, but you're very wrong with the overall statement you are making.

Not all energy advances must make things cheaper per KW directly, not having to deal with (relatively) huge amounts of radioactive waste is a huge benefit worth lots of dough, as is complete safety and many of the other benefits of fusion.

You're completely ignoring the costs of safety and waste handling in the fission reactor. Those are both VERY expensive in themselves (and the latter has for a large part just been put off with temporary solutions until "something better" can be done with the stuff that's cheap enough to be economically viable, so there may not even be a full accounting of the waste handling costs yet.)

Not to mention that the cost of producing the materials needed for fusion is likely to drastically drop once there's been

we won't have uranium and thorium forever, we won't have petroleum and coal forever. at some point, we need to harness fusion. and solar, wind, tidal, geothermal, etc.: boutique sources in terms of the energy demand of a growing population and growing richer population

in the future, they won't talk A.D. and B.C., they will talk A.I. and B.I. (after ignition and before ignition). Because this really will transform the human race in terms of what we can do and instantly rendering so many petty geopolitical and economic problems null and void

and if we never reach A.I.? then we may very well be talking about a future where civilization devolves, and never musters enough willpower and resources to attempt this again. fusion is that important to the future of mankind

oh and thank you MIT Researchers for answering my question, #17

followup question:

how does it feel to know the future of mankind rests on your shoulders?

Yeah, you are right about us having to develop alternative energy sources because we run out of current ones.

One could also try approach things from the opposite end. Stop using so much energy! Why are you typing your comments on an octa-core i7 system when a lowly ARM-based system will do just fine. Why are we running mega server farms and wasting huge amounts of energy and resources in high-end super-game-monster-machines to play games? Why do you take your car to go two blocks when there's sidewalks? Why

The 30ns confinement time is a feature of the design - this is not a "steady state" reactor, it's designed to pulse. They are actually looking for anything above 9ns, so they are succeeding on that metric.

It also states

Ion temperatures of 150keV - this is a good improvement on their older results

Hello. I am not exactly sure of the answer to this question. Our current funding it provided by a DOE contract but I am not sure if there is anything that would prevent us from raising money directly. I am not aware of any such rule. The only problem is, this is very large scale science which is expensive (the current budget proposal for 2013 cuts our budget by 18 million dollars). It would most likely be quite difficult to raise that kind of money yearly to support or research. People in our field

Obviously, having media that are able to explain things clearly and fairly are a necessity.

With the problems of media bias from ALL sides, I fear this would be the biggest political hurdle. The graph of actual funding is sad, but not surprising. The way that most people think about fusion technology, you might as well be talking about teleportation and warp drive.

Cards on the table, I'm a fiscal conservative. At the same time, I realize research like this really requires government funding because the pr

What for The People's Fusion Research Kickstarter Project? Here is a crazy idea: Some people are just fine with their tax money going to fundamental research.
I tire of the tax trolls that plague this site.

I am one of those who is fine with my tax money going to fundamental research, but let's not pretend that it isn't being done by force. For me, the act of taking someone's money and spending it on something that I like has to be outweighed by the benefit to society.

So what? Let's say I concede your point and that I signed your contract when I was by chance born into your country. You are still enforcing a contract with threat of force. Any other contract I sign, there is not a threat of force on the other end.

"Buying a TV on credit is forced payment"

No, because the worst they can do if I don't pay is take the unpaid-for goods away. I cannot go to prison for violating a revolving credit contract. Recent law also allows garnishing of wages, but still no jail time.

I'm fine with, too, but that's a more appropriate response to a voluntary contribution, not a mandatory one. Is it more important that your neighborhood have a public library or that your family have heat in the winter? How about your children? Your grandchildren? What if the library on the corner was built and funded based on a monetary system that eventually meant that your grandchildren would work under involuntary servitude for a totalitarian regime, because they loaned your government the money for

You just went on to, what, suggest that public works projects might leave your descendants slaves to a totalitarian regime?

Well it's looking at a bigger picture, really. This type of research funding is generally a good thing, and will benefit everyone in the long run. But debt is a bad thing, and will harm everyone in the long run. When the debt is $16 trillion and growing, and unfunded obligations are $118 trillion and growing, and the largest external creditor is a totalitarian regime (China), you really need to set some priorities first.

You chose an inflammatory topic, and it was a stupid choice.

That's quite obvious at this point, you are correct. Yet these emotional issues are

Sure, as long as your business or the business you work for which is 'earning' all that money starts paying directly on a per-use basis for the infrastructure on which it depends - you know, roads, the education system which gave you literate workers, a legal and police system to stop anyone with a gun just walking in and taking your hard earned money whenever they feel like it,.. If you really don't think that stuff is necessary, I hear Somalia would love to have you move there and start a business.

Also, the way I've heard it, we already tried that free market approach and it didn't work. So, now, we need stuff like the Jimmy Buffet rules, for better fairness, because wealthy basketball players shouldn't be paying a lower rate on their earnings than Secretariat.

I agree with you in principle, but I wouldn't take any dollar figure at face value. It would probably be more fair to compare the $80BN figure to the pre-war estimate of what Iraq would cost, which was, coincidentally, $50-$60 BN [cnn.com], with an "upper end of a hypothetical" at $200BN. (And unlike the estimate for fusion, the war estimate was based on a previous, seemingly comparable situation - the Gulf War in 1990).

How about, 10% of TARP, which was magically produced overnight, with nary a quibble, on the supposition that if we didn't do it, a few very wealthy bank CEO's would wet their pants with fear, and debt-ratings companies would be outed for the frauds that they so obviously were.

Seriously. $1 Trillion? For free-energy? Forever? Sounds like a deal to me. Where do I sign?

"If" as in "If you had a real argument I'd like to hear it." Your post could be applied to any situation, just replace the names and numbers.

A simple comparison to the Apollo program satisfies me: fusion power is an equal scale investment, with equal scale societal achievement, higher long-term benefits to humanity, and with experts' opinions suggesting comparatively low risk. If we thought Apollo was a good bet at the time, this one's even better.

I still think it is a relevant comparison, in the sense that if someone can agree Apollo was the right bet (especially in light of your point), fusion research investment is at least as good of a bet. And the nice thing is we can work with the international community to share the burden.

America could earn some pride back if it spent less money on world policing and more on forward progress.

Bear in mind the money doesn't get thrown into a pile and burned. It gets spent on researcher salaries, contractor, supports, and so on. So even if the spent 100 billion, and proved it couldn't work, that money was still circulating in society and adding to the economy.

If you'd read, you'd see the number is 40 years off. That's 10 less than 50!

I think you're being unfair with the money begging. Basically, here's what they'd said (by my reading): Fusion power is going to happen. It's a matter of when, not if. But if we want it in a timeframe that most humans are used to working (before most of us are dead and buried) we need to start taking it seriously. Insert allusions to the Manhattan Project and the Apollo Missions, both of which involved pouring a ton of money into a

It's 40 years if they go from ITER -> commercial viable reactor.. but further down, they say ITER will produce 10x more energy for minutes at a time. Pretty sure commercial reactors need to produce electricity for a bit longer than that. And I can't imagine anyone would attempt a commercial reactor when the prototype (ITER) can only operate for a few minutes.

It also assumes, they won't discover some problem with ITER, and that ITER will work as expected (ie: best case scenario).

I acknowledged that in the first sentence. They want to go straight from ITER -> a commercially viable reactor (DEMO). Their 40 year estimate is the rosiest, most optimistic estimate they could come up with.

We want to address that head-on here: aside from a few over-optimistic predictions made in the very early days of magnetic fusion research (the 1950s)...

They then go on to make an over-optimistic prediction, based entirely on best-case scenarios, that it is only 40 years away.

They committed the sin they say others are committing.

This is why fusion has 'the reputation of being “always being thirty years away” (or fifty, or twenty)'...

The answers here make clear for the first time that I've seen in a public place in a long time what the function of NIF is - it is NOT a project oriented towards civil energy generation, but a weapons research project.

They are solving problems, sure, but they are solving problems for their needs, which don't necessarily have applicability to civil energy needs.

Due you think that crowdsourcing might help? Anyone know what it takes to get an experiment going? I mean if we can get $2M for Wasteland 2, surely we could get at least $2M for a fusion experiment. Maybe more if we could get tax deducatable receipts... and a cool (or should I say "hot"?;) ) t-shirt.

Sad that the first response to a very good science article (kudos, slashdot!) is a money-worshiping luddite. Which oil company do you work for, anyway?

Shouldn't you be at Business Week or the Wall Street Journal or FOX rather than slashdot?

How many days of war in Afghanistan will that $80B buy? I not only have no problem with my taxes going to research, I encourage it. As does anyone else with more than a two digit IQ. I sure wish they'd end that damned war, though.

Did you bother reading a word of what was written, or did you just knee-jerk reply without doing so? Considering that yours was the first post, my guess is you thought you knew what you were talking about but don't.

tl;dr version of TFA: They're making progress, and spelled out what progress has been made and what progress still needs to be made.

Many of the answers to that question seem to be "here's an area in which we've improved, and in which we need more improvement". The problem is that it doesn't then state how far along they are. Something like "we improved this from 10% to 50% and we think that 70% is enough" would be very different from "we improved this from 1% to 2% and we need to get to 70%"

I think there's good reason for that. You're basically asking them to evaluate their position on a continuum that isn't actually static. It may be that the next discovery, which for the sake of argument might be predicted to move the project along 10%, actually ends up cutting out half the upcoming work, or adds more unknown and unforeseen problems to be solved.

That's exactly the problem. They're describing their progress in order to justify the claim that they're 50 years away from fusion. If they don't know whether the next step is going to move the project a lot or show that they need to solve even more problems, then how can they know that they are some specific number of years away?

You may have noted that there are no (or certainly not many) oil companies now, they are all called energy companies. This is because they already see the day when oil is too expensive for most people to use for energy, so they are diversifying into other ways of making energy. BP is a huge manufacturer of solar cells, for example. It is entirely probable that today's energy companies would be involved in the future's commercialization of fusion.

$80 billion over 20 years sounds like a reasonable level of funding to me. Sure, it's not money thrown at solar panel companies, but it's in the same vein. Worst case, we learn more about high-energy physics and fusion in particular.

Strictly speaking the Wiffleball device is distinct from a Farnsworth Fusor, though it is related.

The fusor has a problem in that grid losses from a classic electrostatic confinement device are inevitable and will always prevent breakeven operation.

The Bussard Wiffleball avoids this problem (in theory) by eliminating the physical grid and replacing it with magnetic fields (which is why you'll see them referred to as "magrid" devices by some as well).

Promising work, and with more teams working on it now I hope that we will see published work in the not too distant future.

Potential side benefits include many additional data points on magnetic confinement of plasma in regimes not currently covered by Tokamak research, so even if the wiffleball configuration proves to be a bust the results can still be useful.

Why can't the Farnsworth device (FUSOR) be made to work with some smarts and a lot of money?

The short answer is, a Farnsworth style device won't work primarily because the higher you ramp-up the power, the faster you burnout the inner, negative grid. You burnout the grid way before you can get any useful power out.

Dr. Bussard's (RIP) Polywell [wikipedia.org], simply put, tries to cleverly replace the inner grid with a cloud of electrons contained/shaped by a magnetic field to create a virtual negative grid.

Current work on the Polywell is being funded by the Navy and is under a publishing embargo. I assume that since they're still being funded and we haven't heard anything negative, they must at least be hitting their milestones.

I do farnsworth fusors here, on my own money - no external funding/begging required. They're a nice research source of neutrons. Their "dynamic equilibrium" turns out to be the place they are the least efficient, however. I might be the first person to have discovered that and some fairly large increases in Q due to perturbing that.
.

Peer reviewed journals? That's for academics trying to keep others out of the club. Grow a pair boys, and do as I do - just make it all open source - we keep no secrets,

Bah, I think it has more to do with the threatened researchers not wanting to step on any toes as their funding is already in jeopardy. I don't blame them for not wanting to call anyone out. In their situation, I wouldn't either.